Influence of mining ground fissures on soil erodibility in Northern Shaanxi coal mining area of Yellow River Basin

The middle reaches of the Yellow River Basin is not only the coal resourcerich area in China,but also the key area for the prevention and control of soil erosion at the national level.Through mastering the effect of soil erosion caused by coal mining damage,it is conducive to realize the ecological environment protection and high quality development of coal mining area.Taking the mining ground fissures in the mining damage area of North Wing of Ning tiao ta Coal Mine in Northern Shaanxi as the research object,the soil around the ground fissures with widths of 0-20 cm,20-40 cm and 40-60 cm (within a horizontal distance of 80 cm and a vertical depth of 20 cm) were collected respectively.The mechanical composition and organic matter content of soil were measured by MS2 000 laser particle size analyzer and analyzer,and the soil erodibility K-factor was calculated based on EPIC model.The spatial variation characteristics of soil mechanical composition and organic matter content were analyzed,and the effect of soil erosion caused by mining ground fissures on a small spatial scale was interpreted.The results show that:① The mining ground fissures can reduce the clay content of the surrounding soil,with an average decrease of 17.06%-32.66%.The effect is mainly a horizontal negative effect when the crack width is less than 20 cm,and decreases with the increase of horizontal distance.And it is mainly a vertical negative effect when the crack width is larger than 20 cm,and increases with the increase of vertical depth;② The mining ground fissures can reduce the organic matter content of the surrounding soil,with an average decrease of 32.16%-54.01%.And it increases with the increase of crack width and the decrease of horizontal distance;③ The mining ground fissures can improve the erodibility of the surrounding soil and differentiate the erosion resistance between the soil layers.The larger the width of the fissures and the smaller the horizontal distance,the more obvious the effect is.The increase of soil erodibility is mainly within a horizontal distance of 83 cm,which can be used as a target area for precise prevention and control of soil erosion in the coal mining damage area in northern Shaanxi;④ The soil clay content and the organic matter content around the mining ground fissures are highly consistent with the soil erodibility K-factor in a small spatial scale,and the correlation coefficients are -0.569 and -0.757,respectively,reaching a very significant negative correlation level (P<0.01).It is closely related to the fact that mining ground fissures significantly change soil porosity,damage plant root traits and microbial activity.The closer to the mining ground fissure,the higher the potential erosion ability,and the worse the soil erosion resistance is,so the artificial measures should be considered,and the natural measures should be considered on the contrary.So as to provide scientific basis for precise prevention and control of soil erosion and ecological environment protection in coal mining area in the middle reaches of the Yellow River Basin.